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Listen to part of a talk in a botany class.
请听一段植物学课上的演讲。
OK. So we've talked about some different types of root systems of plants, and I've shown you some pretty cool slides,
我们已经讲过一些不同种类的植物的根系，我给你们看了一些很酷的幻灯片，
but now I want to talk about the extent of the root system—the overall size of the root system...the depth.
但我现在想说一下根系的长度——根系的总尺寸，深度。
I want to tell you about one particular experiment. I think you're going to find this pretty amazing.
我要跟你们讲一个特别的实验。我想你们会觉得很惊奇。
OK. So there was this scientist...this very meticulous scientist decided that the best place to see a whole root system—
好了。曾经有一个科学家，这个非常谨慎的科学家认为，最适合观察一整个根系的地方——
to actually see how big the entire system got—the best place would be to grow it...where?
真正地观察整个系统能长到多大——，最好把它种在......哪里？
Um, water?
水里吗？
In water. So he took rye plants—it was rye plants—and he started growing them in water.
在水中。他取了黑麦植株——是黑麦——然后开始在水里种植。
Now, you've all heard of growing stuff in water before, right?
你们以前都听过在水里中东西，对吧？
It's done commercially, right? Uh, like to grow vegetables and flowers?
是商业种植，对吗？比如种植蔬菜和鲜花？
Right. They grow all kinds of commercial crops in water.
对的。他们在水里种植各种商业作物。
So, if you're growing things in water, you can add the fertilizer.
所以，如果你要在水里种东西，你可以加入肥料。
What do you need to do to that water besides put fertilizer in it? Anyone ever actually tried to grow plants in water?
除了在水里加入肥料还要对水做些什么？有人试过在水里种植物吗？
You must bubble water through it. Bubble gas through it. I'm sorry, you must bubble gas through it.
你得往里面充入水。充入气体。说错了，是充入气体。
So, gas, you have to bubble through. Think about the soil we talked about last week, about growing plants in soil.
所以你得往里面充气。想一想我们上周说过的土壤，在土壤中种植植物。
Think about some of you who have killed your favorite houseplants, 'cause you loved them too much.
想一想你们谁杀死了自己最爱的室内植物，因为溺爱。
If you overwater, why do your favorite houseplants die?
如果你浇水过多，你最爱的室内植物就会死，为什么？
Oh, no oxygen.
哦，缺氧。
Not enough oxygen for the roots...which do what twenty-four hours a day in all seasons?
根部没有足够的氧气，一年四季每天都在做的是什么？
Respiration?
呼吸？
Respire...respiration...they breathe.
植物呼吸，呼吸，它们会呼吸。
So, if you just stick rye plants in water, it doesn't make a difference how much fertilizer you add,
所以，如果你只是把黑麦植株插入水中，加入多少肥料并不重要，
you also need to bubble gas through the water, so they have access to that oxygen.
你还需要往水中充入气体，所以它们才能获得氧气。
If they don't have that, they're in big trouble.
如果没有氧气，它们麻烦就大了。
OK. So this guy—this scientist—grew a rye plant in water so he could see the root system how big it got—its surface area.
所以这个家伙——这个科学家——在水中种了一株黑麦以便他观察根系能长到多大——它的表面部分。
I read about this and the book said one thousand kilometers of roots. I kept thinking: this has to be a mistake.
我阅读过这个，书上说，根有一千千米长。我一直在想：这肯定是个错误。
It just doesn't make any sense to me that...that...that could be right.
我觉得没道理，那不是对的。
But that's what all the books have, and no one's ever corrected it.
但是所有的书上都是那样写的，没有人修改过。
